Centralized b all-kill



M. J. BARNETT.

CENTRALIZED BALL MILL.

APPLICATION FILED JULY 5.19l8.

Patented Sept. 23, 1919.

2 SHEETSSHEET 1.

nvvtwnm M. .1. EA RN E 77' M. 1. BA NETT.

CENTRALIZED BALL MILL.

PatentedSept. 23, 1919.

2 SHEETS-SHEET 2. F75, 3

|JLI..... f/ l I INVENTDR M. J. BAH/V577 Tia COLUMBIA PLANOORAPH c0., wAsmNuTuv, I). c,

UNITED srnrns 1 u onnron MORRISSON JhBARNETT, OF SAN FRANCISCO, CALIFORNIA.

onnrnanrznn ALnMrLL.

Specification of Letters Patent. Patented Sept. 23, 1919.

Application filed July 5, 1918.. Serial No. 243,293.

To all whom it may concern: 9

Be it known that I, Monnrssozv J. BARNETT, a citizen of the United-States, residing at San Francisco, in the county of San Francisco and State of California, have invented new and useful Improvements in Central ized Ball-Mills, of which the following is a specification. y

The present invention relates to improvements in mills for grinding and pulverizing ores and the like.

One object of the invention is to provide a mill in which the grinding rollers will be held always to a circular part, and any tendency of the rollers to move )tangentially therefrom will be avoided.

A further object is: to provide an improved feeding mechanism for such a mill whereby the ore may be adjustably fed so that it may be supplied at the same rate as it is disposed of by the mill.

In the accompanying drawing, Figure 1 is a vertical central section of my improved mill; Fig. 2 is a top plan view thereof; Fig. 3 is a view similar to Fig. 1 of a modified form of the invention; Fig. 1 is a similar view of a further modification.

Referring to the drawing, 1 indicates a chute, down which ore is fed by any suitable means, dropping at the bottom of said chute on to an endless draper 2, traveling around rollers 3, 4, and supported between said rollers by idler rollers 6. The ore drops from said draper within a tube 7 supported upon arms 8 extending oppositely from hub sections 9 secured together by screws 11 and surrounding a vertical driving shaft 12, and secured to said shaft by a set screw 13. Said vertical shaft rotates in bearings 14, 16, secured to cross pieces 17, 18, the ends of which are supported by posts 19 erected upon a base 21 and supported by braces 22 on said base. On its upper end said shaft carries a 'bevel wheel 23 which -is driven by a bevel pinion 2 1 on a horizontal shaft 26 having suitable bearings 25, extend ing from the upper cross piece 18 and one of said posts 19 respectively, and carrying a pulley by which it can be driven by a belt from an electric motor or any other suitable source of power.

To the outer end of said arms 8 are loosely attached forward ends of links 28, the rear ends of which are loosely attached, as shown at 29, toan annular wall 31, the lower edge of which is formed integral with an annular driver 32. Said driver rotates with the shaft 12 by reason of its connection therewith through the links 28 and arms 8. In its rotation it is supported by a circular series of rolling crushers in the form of balls 33, which travel in an annular ball race 34 formed of extremely tough iron, and which is contained in an annular cavity 36 in the base 21. Upon said base 21, centrally of the ball race 34, rests a conical distributer 37, the edge of the base of which is contiguous with an inner edge of the ball race. 'The ore, falling within the tube 7, drops into a hopper-shaped guide 38,by which it Is guided on to the central portion of the conical distributer 37. It then falls down the side of said distributer into the ball race 34, and is crushed between said ball race and the circular series of balls 33 therein. Having been thoroughly pulverized, it escapes on the outer side of'said ball race through a screen 39 and into a channel 41 formed in the base 21 and sloping downward on each side of the base from a comparatively shallow portion 42 to a deep portion 43 whence it is discharged by an opening 44: in the base on to a chute 46. An apron 47 surrounds the upper portion of the screen so as to prevent the ore from being projected too far out after passing through the screen.

In order to prevent any tendency of the balls to, move tangentially out of the ball race, the annular driver 32 is of arcuate cross-section and is so formed that its outer portion, that is, the portion outside a cylindrical surface extending through the centers of the balls, is considerably greater than its inner portion. I have found the best construction to be that the outer portion should be twice the width of the inner portion, and that the driver should be in the shape of a quadrantal arc in' cross section, so that the outer portion of the driver is in cross section of the form of a arc and the inner portion ofa 30 arc.

In the same way, the part of the ball race which is in contact with the balls is, in cross section of the form of a quadrantal arc, the inner portion thereof, having regard to said cylindrical surface through the centers of the balls, being a 30 arc, and the outer portion being a 60 arc. These dimensions I have found to give the best results.

In order that the arc may be fed to the mill at precisely the same rate at which the mill can dispose of the arc, the driving roller 4 is rotated by a shaft 51, which carries a friction disk 52, which can be engaged by a friction wheel 54 having a grooved hub 55 and slidable on, but rotatable with, a shaft 56 carrying a pulley 57 driven by a belt 58 from a pulley 59 on the driving shaft 26. Thus the friction wheel 54 can be moved so as to contact with said friction disk 52 at any desired distance from the center of the latter, by means of a shifter 61 engaging the grooved hub 55 of the friction wheel 54 and slidable on a fixed rod 63. The shifter 61 can be clamped at any point of said rod by a clamping screw therein engaging said rod and turned by a head 64. By observation of the rate at which the mill is disposing of the ore fed thereto, and by moving the friction wheel 54 along the shaft 56, it can be insured that the feed of the ore is just sufficient, and no more than sufficient, to supply the mill.

In the forms of the invention shown in Figs. 8, 4, the draper 2 is dispensed with, and the feed is directed through the hollow said distributer.

shaft 12 and the central hole between the arms'S. Said shaft 12 is rotated by an endless rope 66 around a grooved Wheel 67 secured on said shaft. In Fig. 4 it is rotated by a flat band 68 around a band wheel 69 secured on the shaft 12.

I claim 1. A centralized ball mill comprising an annular channel, a circular series of rolling crushers therein, a rotatable driver sup ported by said crushers, a central vertical shaft, arms extending therefrom, and links connected with said arms and driver symmetrically on opposite sides thereof.

2. A centralized ball mill comprising an annular channel, a circular series of rolling crushers therein, a rotatable driver supported by said crushers, a central vertical shaft, arms extending therefrom, links connected with said arms and driver symmetrically on opposite sides thereof, and means for feeding ore on to the central portion of M. J. BARNETT.

copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

